Is Vitamin E dangerous in high doses? (Full Article)f1
Posted: 12 Nov 2004 10:26 AM

In some circumstances, it may be. But these are limited conditions and there are certainly some easy ways to get around them. Let me explain.I am writing this in response to an article to be published this week in Annals of Internal Medicine. Researchers at Johns Hopkins have subjected some Vitamin E studies to a meta-analysis, which is where previously published studies are re-examined and compared in order to try to mine more information out of them. These meta-analyses are often highly speculative, because the protocol for each study is different enough that it becomes a stretch to link the results and imply a common thread runs through them despite the different variables. For example, the supplement tested may be given in different forms or doses, the patient group may have significant differences, the length of time taking the supplement may vary considerably or may even include previous users and new users, etc. There are also differences between natural and synthetic Vitamin E, with most studies using only the synthetic forms that are composed of different-shaped molecules and only half as effective as natural Vitamin E. Natural Vitamin E is called d-alpha tocopherol and synthetic Vitamin E is called dl-alpha tocopherol.

Official U.S. dietary guidelines set an upper tolerable intake limit of up to 1,500 IU per day, based on the scientific record.

While these meta-analyses are academically useful to point to potential new problems or solutions, by no means are they definitive proof of anything, due to the lack of uniform protocols and patient groups. But that won't stop the medical lobby from trying to use these results to limit potencies of vitamins to everyone "for our own good". The doctors and researchers may be well-meaning, but results of this kind of preliminary study can be publicized and take on a life of their own, with a new role as "proof" of the dangers of taking vitamins.

One thing that many of the patients in this analysis of previous studies had in common was being elderly and sick. So the first caution issued by the report's authors is that their speculative findings would not even apply to healthy or younger people. That's one BIG argument against using this analysis to set general restrictions on Vitamin E dosages. We already have some evidence that taking one antioxidant, rather than antioxidant formulas or multiple vitamins, may increase the cancer risks for aged smokers. This may be because antioxidants need to recharge and support each other or else some can actually transform into pro-oxidants that can increase the damage.

I always caution against taking mega-doses of one nutrient without considering potential side effects. Taking only one antioxidant may seem to deplete others because of the way they interact, with one antioxidant chemically supporting others. A surplus of one nutrient may increase a person's need for one or more other nutrients, creating an apparent functional deficiency.

There is a recent example that illustrates my point. Some years ago an antioxidant study in Finland was halted early, with a widely reported increase in cancer rates among male smokers taking beta-carotene. Headlines associated vitamins with cancer risk. Despite objections that the study was flawed, vitamin use dropped.

Fast-forward to this year. A new analysis published in July takes another look at that same Finnish smokers' study, but now takes into account their total antioxidant intake, and clears up that whole controversy. Their risk of getting lung cancer was closely associated with total antioxidants in the diet, with more antioxidants meaning less cancer.

A composite antioxidant index was generated for each of the 27,000 men over 14 years. The calculated amounts of carotenoids, flavonoids, Vitamin E, selenium and Vitamin C were compared to actual lung cancer rates, with a clear result: a combination of antioxidants lowers lung cancer risk in male smokers.

What does this all mean? I think we are in for another round of attacks on vitamins based on this crude analysis of Vitamin E, with some medical experts calling for restrictions on vitamin potency. That would be a mistake, both scientifically and from a public health viewpoint. The message should be that people should not try to take a high dose of one supplement without considering that it may increase our need for other nutrients. Elderly, sick people need a more holistic approach rather than using a single nutrient in high doses, as if it were a drug. Nutrients just don't work well in isolation from each other. Vitamins are essential to health and life, but the average American gets only 1/3 of the recommended daily intake of Vitamin E that would prevent serious illnesses. Most people would benefit from taking a multiple vitamin and a Vitamin E supplement, and it would be safer than just the Vitamin E alone.

That shouldn't be hard for the smart folks at Johns Hopkins to understand.

By Neil E. Levin, CCN, DANLA

REFERENCES:

1. July 2004 American Journal of Epidemiology.
   
   
2. 2. Poster session abstract: High-dose vitamin E supplementation may increase all-cause mortality, a dose response meta-analysis of randomized trials; Ernest N. Morial Convention Center, Exhibit Hall 1-2.) TO BE PUBLISHED: Annals of Internal Medicine, Nov. 10, 2004.

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